By electronic tag is meant an assembly including a support, a near-field communication circuit including an electronic chip and a near-field communication antenna, allowing contactless communication to be established with an external device for exchanging data. The antenna is generally connected to the electronic chip and is used not only as a means of contactless communication, but also to produce the energy needed for power supply to the electronic chip.
In order to ensure optimal transmission of data between the tag and the external device, regardless of the tag's metallic environment, the tag is provided with a magnetic shielding layer capable of protecting the near-field communication circuit.
This offers a particular advantage, especially in a “contactless payment” application carried on a mobile telephone, the mobile telephone including a battery and occasionally even a metal case which can interfere greatly with the quality of data transmission to an external reader when the tag is affixed to the telephone.
A contactless type tag suited for application in a metallic environment is already known in the state of the art, in particular from document WO2008/065278. In this document, the tag includes an intermediate layer made of a magnetically hyper-conductive material, placed against a substrate bearing the antenna and the microcircuit. The assembly made up of the substrate, the antenna and the microcircuit is later embedded in a cover made of plastic by lamination or molding.
The disadvantage of the tag thus obtained is that it is relatively thick due to the presence, in addition to the substrate bearing the antenna and the microcircuit, of the intermediate layer and the cover.
In addition, when it is desired to make tags in various formats, this can lead to problems during customization. In fact, customization equipment must generally be adjusted to the format of the tag to be customized. Further, certain tag formats may not be compatible with customization equipment, which limits considerably the diversity of tags manufactured. Faced with these difficulties, it often happens that customization is frozen at the time the card is manufactured.
There exists at present a need for a tag that is easily customizable, regardless of its shape or format. In addition, this tag must be suited to operate in a metallic environment, as for example next to a mobile telephone.